I found the pixiv tag for this sort of thing.
https://www.pixiv.net/en/tags/%E3%82%B9%E3%82%A6%E3%83%84/artworks
I think a lot of the appeal is in changing the character's social role. They're still completely themself, they still have the same body, the tight formfitting suit or the paint that barely counts as clothing highlights their human form, but they're in the role of an animal instead of a human. I suppose that is another reason why I perfer the images without masks, I don't want the character to be able to hide their identity, it's the difference between the character just becoming an animal, and becoming themself as an animal.
Some characters treat is as a cute thing. Animals aren't ashamed of being seen naked, so now that they are one they don't have to be too. The suit leaves nothing to the imagination, but that's not a problem since they're an animal right now. Wearing the suit is liberating.
Other characters see becoming an animal as a degrading thing. Animals are shameless and primal. In a way, wearing an animal suit is more naked than wearing nothing. Rather than becoming cute, the animal costume strips them of the base level of dignity they get just by being a human.
The fetish plays off the difference between the roles of humans and of animals. Pokemon having slightly different roles from normal animals is probably why they're so popular. Becoming an vulpix is more submissive than becoming a fox, and pokemon all have fun patterns that are more eye catching.
I know that's probably reading too much into it, but that's part of the fun.
>>7854
That Arcanine is nice. I bet those angled stripes would feel really nice, still wet on her body.